The present invention relates to a method and/or architecture for implementing semiconductors generally and, more particularly, to a method and/or architecture for salicidation of cobalt on a semiconductor wafer.
The conventional method of forming cobalt salicide (i.e., self aligned silicide) on a surface of a silicon semiconductor wafer is via the following steps: (i) depositing cobalt on the surface of the wafer using a conventional (i.e., non-directional) DC sputtering system, (ii) depositing either a titanium or titanium/titanium nitride cap over the cobalt layer using the conventional DC sputtering system to getter up oxygen, (iii) reacting the cobalt with the underlying active silicon regions using a first stage rapid thermal process in a temperature range from 400xc2x0 C. to 550xc2x0 C., (iv) chemically stripping the cobalt that was not over silicon and thus not reacted, (v) converting the cobalt silicon compound formed in the first rapid thermal process (i.e., step (iii)) to a fully reacted and converted cobalt salicide using a second rapid thermal process at a temperature range from 700xc2x0 C. to 1000xc2x0 C. The conventional process has many steps and each step (i) costs money, (ii) adds to the cycle time, and (iii) can create scrap when not performed properly.
It would be desirable to have a method and/or architecture for salicidation of a cobalt layer on a semiconductor wafer that (i) implements fewer steps than the conventional method, (ii) reduces costs, and/or (iii) reduces cycle time.
The present invention concerns an apparatus comprising a fixture and a sputtering device. The fixture may be configured to position a semiconductor wafer in a plasma. The sputtering device may be configured to sputter metal atoms onto a surface of the wafer in a direction perpendicular to the surface.
The objects, features and advantages of the present invention include providing a method and/or architecture for forming a cobalt salicide on a surface of a semiconductor wafer that may: (i) eliminate a step in the salicidation process, (ii) reduce production cost, (iii) reduce process cycle time, (iv) minimize wafer damage, (v) provide a uniform distribution of metal ions in the wafer, and/or (vi) increase the accuracy of cobalt distribution within the wafer.